Gov. Gary Herbert has not indicated whether he will sign the bill into law or veto it, although supporters of the bill say they expect him to approve it. If Herbert does nothing by March 8, the measure automatically becomes law.

The bill was prompted by the case of a pregnant teenager last year who paid someone to beat her, hoping to cause a late term abortion.

But critics argue that allowing homicide charges if a woman's "reckless behavior" causes the unborn child to die opens up the possibility that prosecutors could seek a murder conviction against women who miscarry after not wearing their seatbelts or returning to a partner who has a history of physical abuse.

"This could be misconstrued or construed too aggressively," Democratic Utah state Sen. Ross Romero said. "We all make bad choices in our lives and most of them don't come with criminal burdens. This one does, or may, I should say."

Romero was one of only four senators to vote against his chamber's version of the House bill sponsored by Republican state Rep. Carl Wimmer.

Having passed through both chambers, the bill now sits on the governor's desk. He has until March 8 to either sign or veto the bill. If he does neither, it automatically becomes law.

Herbert's spokeswoman Angie Welling said in an e-mail that he has not taken any formal position on the bill.

"He understands that the intent of the bill is not to criminalize miscarriage, nor to restrict a woman's ability to seek a legal abortion. However, he is also aware that concerns exist about possible unintended consequences of the legislation," Welling wrote. "That will be key to his analysis of this legislation, as it is with all other bills with which he is presented."

Introduced to the state Legislature in the fall, the bill was in response to a 17-year-old pregnant girl from Vernal who was arrested and accused of paying someone to beat her to force a late-term miscarriage.

The attempted abortion failed and the child was born healthy. Aaron Harrison, the 21-year-old charged in the beating, pleaded guilty to second-degree felony attempted murder. He was sentenced to up to five years in prison, according to The Associated Press, but could serve as many as 20 for other unrelated felonies.

A judge, however, set the teen girl free, ruling that her actions were protected by the state's definition of an abortion. It was a ruling that shocked several of Utah's lawmakers, including Wimmer.

"It revealed a weakness and a loophole in our law, which we did not know was there," he said. "We thought all along, we have a criminal homicide law that deals with unborn children and we thought that law was adequate and we found out that it was wanting."

Critics Call Miscarriage Bill a 'Knee-Jerk' Reaction

Like many other states, Utah's law regarding the death of unborn fetuses punishes the woman's attacker, not the woman herself.

Opponents to Wimmer's legislation say the new proposal swings too far in the other direction, most frequently citing the example about the woman who returns to a physically abusive partner.

"It would never happen," Wimmer said, referring to accusations that women would be prosecuted for careless behavior. He believes the state's definition of "reckless" would protect women in those types of circumstances. "Reckless is behavior where you know that a threat exists, where you know that there's a risk, an unjustifiable risk."

Romero, who called Wimmer's bill "misguided," said the proposal misses a huge opportunity to react to the 17-year-old's hired beating, dealing with the mental health issues and other circumstances that led her to feel a planned assault was her best option.

"This doesn't really get to what's going on," he said. "Obviously the problem with that situation and with situations like that is the person needs counseling, needs intervention much more than they need incarceration or criminal penalties."

Jordan Goldberg, state advocacy counsel for the New York-based Center for Reproductive Rights has been following the Utah bill since its inception.

"One of the biggest problems of the law is that it's criminalizing women's behavior during pregnancy," she said. "When you start down that path, it's very difficult to draw the line."

Proposed Bill Means Tighter Restrictions on Abortions in Utah

Romero said he also has serious concerns about the bill's underlying effect of allowing the state to put an even tighter rein on abortion rights. The proposal includes a new state definition of abortion as "only to a medical procedure carried out by a physician, or through a substance used under the direction of a physician."

"This type of attention on the woman, I think, may be part of this whole general assault on a woman's right to choose," he said.

It's a charge Wimmer calls a fair one.

"If he's insinuating because I ran this bill, because I'm pro-life and anti abortion and I'm doing everything in my power to restrict abortions in Utah, then he's absolutely correct," Wimmer said.

"The intent was to make sure that the cases like the Vernal situation does not happen again, and we also narrowly defined abortion to further restrict abortions even more than we already have," he said.